Add token-based authentication to frontend, connector and database for each connector

[daku-de]

User story

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As a user, I would like to verify my identity via token-based authentication.

Acceptance Criteria

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• When the user inputs the right login credentials. The frontend should send a token request to the backend so that the backend can send the user a unique access token. This access token is used so that user does not have to reenter credentials as long as the token remains valid.
• The token-based authentication should be implemented for each components (frontend, connector dashboard and database)

  DoD General Criteria

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• Feature has been merged into the main branch
• Feature has been added to the documentation
• Product owner approved features
• Developers agreed to release